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Zoom lens and imaging apparatus

a zoom lens and imaging apparatus technology, applied in the field of zoom lenses and imaging apparatuses, can solve the problems of large lens group, difficult to achieve wide angle, and large outer diameter of the lens closest to the object side and the outer diameter of the lens disposed, and achieve the effect of high optical performan

Active Publication Date: 2021-04-29
FUJIFILM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The proposed lens configuration achieves a small-size zoom lens with high optical performance and a wide angle of view by optimizing the refractive indices, Abbe numbers, and movement of lens groups, thereby reducing aberrations and lens diameter, and enhancing autofocusing speed.

Problems solved by technology

Since the low-dispersion material has a low refractive index, an average refractive index of the first lens group becomes low, and thus, it is difficult to achieve the wide angle.
However, in a case where this distance is widened, there is a problem that the outer diameter of the lens closest to the object side and the outer diameter of the lens disposed so as to be close to the object side within the first lens group become large.
The zoom lens described in JP2013-015621A has also a problem that the movement amount of the focusing lens group is increased due to a low refractive power of the focusing lens group.
The zoom lens described in JP2015-203735A has also a problem that the movement amount of the focusing lens group is increased due to the low refractive power of the focusing lens group.

Method used

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  • Zoom lens and imaging apparatus

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0092]Cross-sectional views of a zoom lens according to Example 1 and schematic movement loci are shown in FIG. 2. FIG. 2 shows a state where the object at infinity is in focus, where the left side of the drawing is the object side and the right side of the drawing is the image side. In FIG. 2, a wide-angle end state is represented at an upper part labeled by “wide-angle end”, and a telephoto end state is represented at a lower part labeled by “telephoto end”. Between the upper part and the lower part of FIG. 2, the schematic movement locus of each lens group in a case where zooming from the wide-angle end to the telephoto end is performed is represented by an arrow for each lens group moving during zooming, and a ground symbol is represented for the lens group fixed with respect to the image plane sim during zooming.

[0093]The zoom lens according to Example 1 consists of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive pow...

example 2

[0106]FIG. 3 shows cross sections and schematic movement loci of a zoom lens according to Example 2. The zoom lens according to Example 2 consists of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a negative refractive power, and a fourth lens group G4 having a positive refractive power in order from the object side to the image side. During zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side, the second lens group G2 and the third lens group G3 move to the object side, and the fourth lens group G4 is fixed on to the image plane Sim. Thus, all the distances between the adjacent lens groups change. The first lens group G1 consists of five lenses such as lenses L11 to L15 in order from the object side to the image side, the second lens group G2 consists of an aperture stop St and ten lenses such as lenses L21 to L30 in order from the obje...

example 3

[0108]FIG. 4 shows cross sections and schematic movement loci of a zoom lens according to Example 3. The zoom lens according to Example 3 consists of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a negative refractive power in order from the object side to the image side. During zooming from the wide-angle end to the telephoto end and the first lens group G1 moves to the image side, the second lens group G2, the third lens group G3, and the fourth lens group G4 move to the object side. Thus, all the distances between the adjacent lens groups change. The first lens group G1 consists of five lenses such as lenses L11 to L15 in order from the object side to the image side, the second lens group G2 consists of an aperture stop St and five lenses such as lenses L21 to L25 in order from the object side to the image side, the thi...

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Abstract

A zoom lens includes a negative first lens group, a positive second lens group, and a subsequent lens group in order from an object side. A focusing lens group closer to an image side than the first lens group moves during focusing. The first lens group consists of a first-a lens group and a first-b lens group in order from the object side. Assuming that an average of refractive indices of the negative lenses of the first-a lens group is Nd1ave, a focal length of the focusing lens group is ff, and a focal length of the first lens group is f1, Conditional Expression (1) of 1.73<Nd1ave<1.95 and Conditional Expression (2) of 1<|ff / f1|<3 are satisfied.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a Continuation of U.S. patent application Ser. No. 16 / 355,942 filed Mar. 18, 2019, which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2018-064597, filed on Mar. 29, 2018. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.BACKGROUND OF THE INVENTION1. Field of the Invention[0002]The present invention relates to a zoom lens and an imaging apparatus.2. Description of the Related Art[0003]In the related art, a wide-angle zoom lens is used as an imaging lens such as a digital camera. A configuration in which a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a subsequent lens group are arranged in order from an object side to an image side has been known as a configuration of the wide-angle zoom lens. For example, in JP2016-090748A, JP2013-015621A, JP2015-203735A...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G02B15/163G02B15/177
CPCG02B15/163G02B13/009G02B15/177G02B9/62G02B13/0045G02B27/0025G02B9/60G02B13/18G02B15/14G02B9/34G02B5/005G02B15/20G02B13/04G02B15/145523G02B13/02
Inventor KAWAMURA, DAIKI
Owner FUJIFILM CORP